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<br />1. The applicant has committed to a five-foot mining setback from the pipeline easement <br />boundaries. In order to assure that the setback is maintained, the Division will require that the <br />right-of way be delineated and marked. The applicant must provide a clearly written <br />commitment to have the right-of-way surveyed by a licensed surveyor, and to erect a fence or <br />other durable and clearly visible marker along the boundary. <br />2. The applicant has committed to mining temporary cut slopes at an angle no steeper than 1:1. <br />Typically, gravel pits are mined by excavation at the toe of a gravel bank, whereby the bank <br />collapses progressively into the pit, usually at a near vertical slope. It has been the Division's <br />direct experience that efforts to maintain the mined face at a slope no steeper than 1:1 aze rarely <br />successful unless the operator mines the gravel by pushing material down the bank using a <br />bulldozer, in which case safety considerations require that slopes no steeper than 2.5:1 or 3:1 be <br />developed. For this reason, the applicant must describe in terms of the mechanics of eazth <br />moving the procedures to be used to mine at a 1:] slope. It must be emphasized to the applicant <br />that under the mine plan as it is proposed, the Division would consider mining of the slopes <br />parallel to the pipeline at a slope angle steeper than ]:1 at any point during the excavation of the <br />pit to be a serious violation for which an enforcement action would be immediately <br />implemented. <br />3. As discussed above, the Division is satisfied that the proposed mine plan will be protective of <br />the pipeline easement from the standpoint of bulk stability. However, small strains may be <br />sufficient to adversely affect the pipeline, and for this reason the installation of pvo or three <br />strain gauge emplacements on the pipeline would be a reasonable and prudent measure to detect <br />any small movements in the pipeline that map occur. Eazly detection of small movements in the <br />pipeline would allow for timely stress relieving measures that would prevent damage. In <br />summary, the Division's position on the installation of strain gauges is that <br />• The gas pipeline is a critical stmcture, and the consequences of a failure of the pipeline could <br />be catastroplilc. As such, a high degree of conservatism is called for in determining <br />appropriate measures to protect the pipeline. <br />• The steam gauges aze an accepted and easy-to-use pipeline-monitoring device that can be <br />installed at a reasonable cost. The added degree of pipeline protection provided by strain <br />gauges can be realized relatively inexpensively; requiring their installation is a prudent <br />addition to the proposed mine plan. <br />Strain gauge installation and monitoring will require the cooperation of the pipeline operator. If <br />such cooperation cannot be secured, the Division would consider proposals for alternate <br />monitoring methods. Stain gauge specifics and alternate monitoring devices aze discussed <br />further below. <br />4. It is stated in the geotechnical report included with the Tellier Pit application that Public Service <br />Company .vas consulted concerning the design provided for haul road crossings over the <br />pipeline easement. In order to satisfy the regulatory requirement for an engineering <br />demonstration, the Division could accept either documentation that the proposed haul road <br />design is acceptable to Public Service Company, or a rigorous engineering evaluation. The <br />components required for a rigorous evaluation would be the maximum external pressure that <br />may be applied to the pipe by the cover soil and vehicle traffic (including an impact factor of 2 <br />for the moving load), the diameter and shell thickness of the pipe, the composition of the pipe, <br />and a safety factor. Also, it is not cleaz if the five foot thick haul toad embankment proposed fot <br />2 <br />